Malice (1993) [Paula Bell]: Beaten to death (off-screen) by a rapist; her body is shown afterwards when Bill Pullman discovers her in the bushes.

Se7en (1995) [Tracy Mills]: Decapitated (off-screen) by Kevin Spacey. It's strongly implied, but never actually shown or stated outright, that Spacey has her head in a box that he shows to Brad Pitt.

Shakespeare in Love(1998) [Viola de Lesseps]: "Stabs" herself while acting in "Romeo & Juliet" in a play-within-the-film sequence (using a red cloth for stage blood). (Thanks to Todd)

Sliding Doors (1998) [Helen Quilley]: In one of the two parallel realities, she is hit by a truck and later dies in the hospital with John Hannah sitting at her bedside. (She survives in the other timeline.)

Sylvia (2003) [Sylvia Plath]: Commits suicide by sticking her head in a gas oven; the movie opens with a scene of her body lying on the floor, then shows her earlier life in flashback.

Country Strong(2010) [Kelly Canter]: Commits suicide (off-screen) by taking an overdose of sleeping pills; her body is shown afterwards when Garrett Hedlund and Tim McGraw discover her and rush her to the hospital. (Thanks to Andrew and Tommy)

Contagion(2011) [Beth Emhoff]: Dies (off-camera) of the MEV-1 virus; we last see her having a seizure in the hospital as the doctors send Matt Damon out of the room, and a doctor informs Matt of her death shortly afterwards. Her body is shown later on during her autopsy. (Thanks to Tommy)